The invention relates to an airbag having at least one aperture provided in an airbag shell to which a closure element is attached. Moreover, the invention relates to a method of operating a vehicle occupant protection system.
Such airbag is described, for example, in DE 10 2007 058 656 A1, where a closure element including discharge orifices is attached to the aperture in the airbag shell so that it forms an extension of the airbag wall adapted to be outwardly and inwardly everted. The closure element is connected to a tether and by the latter can be pulled into the interior of the airbag so as to close the discharge orifices. For opening the discharge orifices the closure element is forced outwardly by the gas pressure.
EP 1 418 093 B1, too, illustrates an airbag having a closure element to be everted out of the airbag, the closure element in this case being a narrow hose having an end-side discharge orifice. As a standard, the hose and is drawn into the interior of the airbag shell and is connected to a release device via a tether. Prior to actuating the release device the closure element is forced against the inner wall of the airbag shell by the internal pressure within the airbag and the discharge orifice is closed. After actuating the release device the closure element is everted out of the airbag shell due to the internal pressure of the airbag and the gas may flow off through the discharge orifice. It is a drawback, inter alia, that only a small amount of gas may pass the long narrow hose, which impedes rapid ventilation.
The present invention suggests improvements to the afore-described concept of ventilating an airbag.